1. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero Chapter 1 Exploring Life

2. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Overview: Biology’s Most Exciting Era Biology is the scientific study of life Biologists are moving closer to understanding : – How a single cell develops into an organism – How plants convert sunlight to chemical energy – How the human mind works – How living things interact in communities – How life’s diversity evolved from the first microbes

3. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 1.

4. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 2. Emergent Properties New properties that emerge with each step upward in the hierarchy of life, owing to the arrangement and interactions of parts as complexity increases. Examples:

5. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Emergent Properties of Systems Emergent properties result from arrangements and interactions within systems New properties emerge with each step upward in the hierarchy of biological order

6. Ecosystems The biosphere Organisms Populations Communities Cells Organelles Molecules Tissues Organs and organ systems Cell 1 µm Atoms 10 µm 50 µm 3.

7. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 3. A Hierarchy of Biological Organization 1.Biosphere: all environments on Earth 2.Ecosystem: all living and nonliving things in a particular area 3.Community: all organisms in an ecosystem 4.Population: all individuals of a species in a particular area 5.Organism: an individual living thing

8. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings A Hierarchy of Biological Organization (continued) 6.Organ and organ systems: specialized body parts made up of tissues 7.Tissue: a group of similar cells 8.Cell: life’s fundamental unit of structure and function 9.Organelle: a structural component of a cell 10. Molecule: a chemical structure consisting of atoms

9. LE 1-8 Membrane Cytoplasm EUKARYOTIC CELL PROKARYOTIC CELL DNA (no nucleus) Membrane 1 µm Organelles Nucleus (contains DNA) 4.THE CELL

10. A Closer Look At Cells 25 µm

11. LE 1-6 Sperm cell Nuclei containing DNA Egg cell Fertilized egg with DNA from both parents Embryo’s cells With copies of inherited DNA Offspring with traits inherited from both parents A Closer Look at Cells

12. LE 1-7 DNA double helixSingle strand of DNA Nucleotide Cell Nucleus DNA Heritable Information

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15. Regulatory systems ensure a dynamic balance in living systems Chemical processes are catalyzed (accelerated) by enzymes Many biological processes are self-regulating: the product regulates the process itself In negative feedback, the accumulation of a product slows down the process itself In positive feedback (less common), the product speeds up its own production Animation: Negative Feedback Animation: Negative Feedback Animation: Positive Feedback Animation: Positive Feedback

16. LE 1-11 Enzyme 1 A A B B C C D D D D D D D D D D D Enzyme 2 Enzyme 3 Negative feedback Enzyme 1

17. LE 1-12 W Enzyme 4 W X X Y Y Z Z Z Z Z Z Z Z Z Z Enzyme 5 Enzyme 6 Positive feedback Enzyme 4 Enzyme 6 Enzyme 5 Z Z Z Z Z Z Z Z Z

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19. A Closer Look at Ecosystems Each organism interacts with its environment Both organism and environment affect each other

20. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Ecosystem Dynamics The dynamics of an ecosystem include two major processes: – Cycling of nutrients, in which materials acquired by plants eventually return to the soil – The flow of energy from sunlight to producers to consumers

21. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Energy Conversion Activities of life require work Work depends on sources of energy Energy exchange between an organism and environment often involves energy transformations In transformations, some energy is lost as heat Energy flows through an ecosystem, usually entering as light and exiting as heat

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26. Themes of Biology 1.The Cell – basic unit of structure and function 2.Heritable Information – DNA is the form for which life continues through inheritance 3.Emergent Properties – hierarchical organization where new properties emerge 4.Regulation – Feedback mechanisms 5.Interactions with the Environment – exchange of material and energy 6.Energy and Life- work requires energy

27. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Themes 7.Unity and Diversity – diversity is shown in 3 domains but all is connected (DNA) 8.Evolution – explains unity and diversity 9.Structure and Function – correlated at all levels 10.Science as a Process – Scientific Inquiry – Science, technology and society

28. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings #5 – Common terms Eukaryotic Cell - Prokaryotic cell DNA Genes Genome Negative feedback/ Positive feedback

29. LE 1-14 Ursidae Ursus Carnivora Mammalia Chordata Animalia Eukarya SpeciesGenus Family Order Class Phylum KingdomDomain Ursus americanus (American black bear) 6. The Core Theme: Evolution accounts for unity and diversity of life

30. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 7. The Three Domains of Life At the highest level, life is classified into three domains: – Bacteria (prokaryotes) – Archaea (prokaryotes) – Eukarya (eukaryotes) Eukaryotes include protists and the kingdoms Plantae, Fungi, and Animalia

31. LE 1-15 Bacteria 4 µm 100 µm 0.5 µm Kingdom Plantae Protists Kingdom Animalia Kingdom Fungi Archaea

32. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Concept 1.4: Evolution accounts for life’s unity and diversity

33. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

34. 8. Charles Darwin The evolutionary view of life came into sharp focus in 1859, when Charles Darwin published On the Origin of Species by Natural Selection “Darwinism” became almost synonymous with the concept of evolution The Origin of Species articulated two main points: – Descent with modification (the view that contemporary species arose from a succession of ancestors) – Natural selection (a proposed mechanism for descent with modification)

35. LE 1-20 Evolution of adaptations in the population Differences in reproductive success Overproduction and competition Population of organisms Hereditary variations 9.

36. LE 1-21 Population with varied inherited traits Elimination of individuals with certain traits Reproduction of survivors Increasing frequency of traits that enhance survival and reproductive success Natural selection can “edit” a population’s heritable variations An example is the effect of birds preying on a beetle population

37. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Video: Soaring Hawk Video: Soaring Hawk Natural Selection – adaptation

38. LE 1-23 Large ground finch Large cactus ground finch Sharp-beaked ground finch Geospiza magnirostris Geospiza conirostris Medium ground finch Geospiza fuliginosa Small ground finch Woodpecker finch Camarhynchus psittacula Large tree finch Medium tree finch Cactus ground finch Geospiza difficilis Cactus flower eaters Geospiza scandens Seed eater Ground finches Seed eaters Tree finches Common ancestor from South American mainland Insect eaters Bud eater Warbler finches Mangrove finch Geospiza fortis Cactospiza pallida Small tree finch Camarhynchus pauper Camarhynchus parvulus Green warbler finch Gray warbler finch Certhidea olivacea Certhidea fusca Vegetarian finch Platyspiza crassirostris Cactospiza heliobates 10.

39. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Tree of Life Many related organisms have similar features adapted for specific ways of life Such kinships connect life’s unity and diversity to descent with modification Natural selection eventually produces new species from ancestral species Biologists often show evolutionary relationships in a treelike diagram [Videos on slide following the figure]

40. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Concept 1.3: Biologists use various forms of inquiry to explore life Inquiry is a search for information and explanation, often focusing on specific questions The process of science blends two main processes of scientific inquiry: – Discovery science: describing nature – Hypothesis-based science: explaining nature 11.

41. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 12-13. Types of Data Data are recorded observations Two types of data: – Quantitative data: numerical measurements – Qualitative data: recorded descriptions

42. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 14. Hypothesis-Based Science In science, inquiry usually involves proposing and testing hypotheses Hypotheses are hypothetical explanations

43. LE 1-25a Hypothesis #1: Dead batteries Hypothesis #2: Burnt-out bulb Observations Question The Role of Hypotheses in Inquiry In science, a hypothesis is a tentative answer to a well-framed question A hypothesis is an explanation on trial, making a prediction that can be tested

44. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 15.A Closer Look at Hypotheses in Scientific Inquiry A scientific hypothesis must have two important qualities: – It must be testable – It must be falsifiable

45. LE 1-25b Hypothesis #1: Dead batteries Hypothesis #2: Burnt-out bulb Test prediction Test falsifies hypothesis Prediction: Replacing batteries will fix problem Prediction: Replacing bulb will fix problem Test prediction Test does not falsify hypothesis 16-17.

46. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 19. Designing Controlled Experiments Scientists do not control the experimental environment by keeping all variables constant Researchers usually “control” unwanted variables by using control groups to cancel their effects

47. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 20. Limitations of Science The limitations of science are set by its naturalism – Science seeks natural causes for natural phenomena – Science cannot support or falsify supernatural explanations, which are outside the bounds of science

48. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 21. Theories in Science A scientific theory is much broader than a hypothesis A scientific theory is: – broad in scope – general enough to generate new hypotheses – supported by a large body of evidence